US2314395A - Clamshell bucket - Google Patents

Description

March 23 1943. E. 1.. HARRINGTON CLAMSHELL BUCKET Filed Oct. 17, 1941 2 Sheets-Sheet l o e o m o m o o mu md o o mmd m March 23,1943. E. L. HARRlN GTON 2,314,395v

CLAM'SHELL BUCKET Filed Oct. 17, 1941 2 Sheets-Sheet 2 INVENTOR 50 17 620 Lflarringfon M M 6M Patented Mar. 23, 1943 CLAMSHELL BUCKET Edward L. Harrington, Pittsburgh, Pa., assignor to Blaw-Knox Company, Pittsburgh, Pa., a corporation of New Jersey Application October 17, 1941, Serial No. 415,387

3 Claims. (01. 37186) This invention relates to material-handling buckets and in particular to buckets including a pair of scoops hinged together or to a lower sheave block, generally designated as clamshell buckets.

Clamshell buckets hav been used, for many years and have been the subject of numerous improvements. In the present, state of the art, however, they are still characterized by certain objectionable features. For example, to provide the strength necessary to withstand the very severe conditions of use to which clamshell buckets are subject, it has been customary to utilize massive castings for certain portions thereof, particularly the hinges for the scoops proper. This construction' is heavy and expensive but has continued in use nevertheless, for lack of anything better. Since the capacity of the hoist on which a bucket is suspended limits the total safe load, the weight of the empty bucket determines the net amount of material which can be handled therein.

Certain limitations are imposed by accepted foundry practice, furthermore, on the permissible size and shape of complex parts such as bucket hinges. It is impossible for this reason to design a. hinge casting with a View solely to the most efficient use of the metal and as a result, the casting is heavier in parts, at least, than would be necessary if all the metal were used at th point of maximum efficiency.

I have invented a novel clamshell bucket construction which largely eliminates the castings used heretofore, particularly for the hinges to which the scoops are secured for cooperative pivotal movement. In a preferred embodiment of the invention, I provide a rigid hinge frame fabricated principally from metal plate, for each coop proper, the scoop being secured to the frame as by rivets and being replaceable when worn. The hinge frames are pivotally related, i. e., hinged together or to a lower sheave block. Each frame comprises a pair of spaced hinge plates connected by a back plate of angle section. The hinge plates have flanges welded to their rear or outer edges and their lower portions are spaced farther apart the upper ends of the hinge plates. Corner brackets riveted to the outside of the hinge plates, the

flanges thereof and the back plate, provide bearings for pins by which the scoops are pivoted to bucket-supporting arms.

For a complete understanding of the various details of my invention and the novel features and advantages thereof, reference is made to the following complete description and the accompanying drawings illustrating the preferred embodiment briefly outlined above. In the drawmgs,

Figure l is a partial side elevation of a bucket embodying the invention;

Figure 2 is a. partial end view;

Figure 3 is an end view of one of the hinge frames with parts omitted;

Figure 4 is a section through one of the hinge frames taken along the line IV-IV of Figure 3, showing a scoop ready to be attached to the frame;

Figure 5 is a section through one of the side plates of a hinge frame taken along the line V--V of Figure 1;

Figure 6 is a partial section through one of the side plates of one of the hinge frames taken along the line VIVI of Figure 1; and

Figure '7 is a partial end elevation with parts omitted, showing the manner of securing together the back plate, the hinge side plates and the flanges of the latter.

Referring now in detail to the drawings, a bucket embodying my invention is indicated generally at Ill and comprises cooperating scoops ll secured to the lower portions of hinge frames 12 extending upwardly therefrom. The hinge frames are pivoted to the lower ends of corner arms l3 and to a lower sheave block IS. The corner arms l3 are pivoted at their upper ends in the known manner to a head block (not shown) provided with suitable upper sheaves. The bucket is oper ated in the known manner by a closing cable I6 reeved over the sheaves of the block l5 and those of the head block, and a holding cable secured to the latter.

The details of the block l5 and the head block form no part of the present; invention and they will not. therefore, be further described in detail. My invention concerns particularly the V hinge frames 12 and the pivotal mounting thereof on the corner arms l3. The scoops II are of known construction, each including side plates I1 and a bottom plate 18 welded together with reinforcing corners I9 and suitably built-up biting jaws 20 extending around their cooperating inner edges. The scoops are secured to the hinge frames by rivets 2| and may be removed for replacement by shearing off the heads of these'rivets and punching them out. Figure 4 shows a scoop separated from its hinge frame.

stiffening plates 23 are disposed inside each side;

plate and are shaped to conforming contour. The plates 23 are secured to the plates 22 by rivets (not shown). As shown in Figure 5, the rivets zlsecuring the scoops to the hinge frames extend through the side plates 22 adjacent the lower edge thereof and also the stiffening plates 23 in the regions in which the latter overlap the side plates 22.

Alined holes are formed in the plates 22 and 2 adjacent the upper ends thereof to receive hinge bearings 24 which are welded to the plates and provided with bushings 25. Hinge pins 26 extend through the bushings 25 and are secured to the sheave block l5. By this construction, the hinge fnames l2 turn on the pins 26 when the lower sheave block I5 is permitted to descend while the bucket as a whole is suspended on the holding cable. Meshing gear segments 21 are secured to the side plates of the hinge frames l2 to insure proper cooperation of the scoops I l and hinge frames. Each side plate has an arcuate edge portion connecting the upper ends of the inner and outer side edges thereof, adapted to engage the inner surface of the gear segments.

Flanges 28 of metal plate are welded to the outer edges of the side plates 22. As shown in Figure 3, the flanges 28 are shaped to conform generally to the contour of the side plates and to provide inwardly extending flanges having a width much greater for the most part than that of the external flanges. The upper ends of the flanges 28 are bent around the upper ends of the side plates and are provided with bumping blocks 29. The blocks 29 on the two sides of the bucket provide stop portions which cooperate when in abutment, to limit the extreme openmost position of the bucket scoops and hinge frames.

A cross bracing member 30 extends between the side plates of each hinge frame l2 and is firmly secured thereto by brackets 3|. These brackets are welded to the side plates 22 and the member 38 is welded to the brackets, to the side plates and also to the flanges 28 of the side plates. The flanges have an extended lap over the member 30 in flatwise engagement therewith because of their greater width on the inside of the plates 22 than on the outside thereof. The flanges taper upwardly and downwardly from the region of contact with member 38.

A back plate 32 of angle section connewts the side plates 22 of each hinge frame at their outer ends. The plate 32 is notched at its upper corners as shown in Figures 3 and 7 to receive the lower ends of the flanges 28 and is welded at its ends to the side plates 22 and flanges 28 thereof. The outer corners of the plates 22 are cut ofi to provide generally vertical side edgeportions for abutting engagement by the plate 32.

Bearing brackets 33 are attached as by riveting or weldin to the lcwerouter corners f each hinge frame. Only one of the brackets is illustrated in Figure 3, the other being omitted to reveal the construction of the frame. Each bracket 33 has angularly disposed walls 34 and '15 35 adapted to overlap, respectively, and have flatwise engagement with, the outer surfaces of the back plate 32 and the side plates 22 at their meeting corner. Each bracket also has spaced eyes 36 extending upwardly therefrom adapted to receive bearings 31 formed at the lower ends of the corner arms I3. Pins 38 extending through the eyes 36 and the bearings 31 provide a pivotal mounting for the hinges l2 and the scoops H secured thereto on the corner arms [3.

-The brackets 33 are secured to the hinge frames I2 by rivets. They do not, however, overlap any portion of the scoops proper. As a result, the scoops may be removed without removing the corner. brackets. At the same time, any corner bracket may be removed by cuttin out the welds, or shearing off and punching out the rivets as described, without disturbing any other part of the structure. The corner brackets are protected from fouling against rigid structures such as a ships hatch by inclined skids 39. If the bucket on being raised should swing sidewise against a fixed membenthe skids 39 cause the bucket to swing away so that the bracket clears the fixed member.

It will be apparent from the foregoing description and explanation that the invention provides a bucket construction and particularly a hinge frame therefor characterized by important ad vantages over such devices as made heretofore. In the first place, I provide a hinge frame fabri cated almost entirel from metal plate, the only castings employed being the gear segments and the corner brackets. By this construction, the hinge frame may be made much lighter and stronger than a casting of the same size. The side plates of the frame are firmly secured together and the entire structure is rigid and possesses great strength and resistance to bending and twisting stress. This results partly from the extensive overlap of the cross-tie by the flanges of the side plates of the hinge frame. The flanges also serve to prevent straightening out of the side plates which are formed by bending up flat rolled plate.

The scoops may be readily removed from the hinge frames and the same is true of the corner brackets and the removal of one does not require removal of the other.

Although I have illustrated and described but a preferred embodiment of my invention, it will be understood that changes in the construction or arrangement of the parts may be madewithout departing from the spirit of the invention or the scope of the appended claims.

I claim: l

1. In a grab bucket, a pair of rigid self-support; ing hinge frames, each adapted to have one of a pair of cooperating bucket scoops secured thereto, each frame comprising a pair of spaced side plates roughly triangular in outline and having a gen erally horizontal bottom edge, a generally vertical inner side edge and an outer side edge sloping downwardly and outwardly, the outer corners of the plates being cut off to provide generally ver-& tical outer side edge portions,"a back plate abutting said last mentioned portions and having a flange overlying said outer side edges at the lower portions thereof, the upper ends of said side plates being shaped to provide stop portions on the two frames effective to limit the opening movement thereof, flange plates bent to the shape of said outer side edges and welded flatwise thereto and extending from said back plate upwardly along said outer side edges andaround said stop portions, a cross bracing member extending between and secured to said flange plates and presenting a flat surface in engagement therewith, said flange plates lapping said flat surface, and corner brackets fitting over the outer lower comers of said frame and having portions in flatwise engagement with said back plates, said side plates and said flange plates.

2. In a grab bucket, a pair of rigid self-supporting hinge frames, each adapted to have on of a pair of cooperating bucket scoops secured thereto, each frame comprising a pair of spaced side plates roughly triangular in outline and having a generally horizontal bottom edge, a generally vertical inner side edge, and an outer side edge sloping downwardly and outwardly, the outer corners of the plates being cut off to provide generally vertical outer side edge portions, a back plate abutting said last mentioned portions and having a flange overlying said outer side edges at the lower portions thereof, the upper ends of said side plates being shaped to provide stop portions on the two frames effective to limit the opening movement thereof, flange plates bent to the shape of said outer side edges and Welded flatwise thereto and extending from said back plate upwardly along said outer side edges and around said stop 7 portions, a cross bracing member extending between and secured to said flange plates and presenting a flat surface in engagement therewith, said flange plates extending inwardly a greater distance from said side plates adjacent said member than at other points and tapering upwardly and downwardly therefrom, and corner brackets fitting over the outer lower corners of said frame an having portions in flatwise engagement with said back plates, said side plates and said flange plates.

3. In a grab bucket, a pair of rigid self-supporting hinge frames, each adapted to have one of a pair of cooperating bucket scoops secured thereto, each frame comprising a pair of spaced side plates roughly triangular in outline and having a generally horizontal bottom edge, a generally vertical inner side edge, and an outer side edge sloping downwardly and outwardly, the outer corners of the plates being cut off to provide generally vertical outer side edge portions, a back plate abutting said last mentioned portions and having a flange overlying said outer side edges at the lower portions thereof, the upper ends of said side plates being shaped to provide stop po-rtions on the two frames effective to limit the opening movement thereof, flange plates bent to the shape of said outer side edges and welded flatwise thereto and extending from said back plate upwardly along said outer side edges and around said stop portions, each of said plates having an arcuate edge portion connecting the upper ends of the inner side edge and the outer side edge, and a gear segment secured to said arcuate' edge portion, the segments on the two frames meshing to control the angular movement of the frames on opening or closin movement of the scoops.

EDWARD L. HARRINGTON.

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